Projector light source having three cooling airflow delivery ports

ABSTRACT

A light source device includes a reflector that reflects light received from an arc tube toward an illumination receiving area, and a housing that houses the reflector to form a space through which cooling air for cooling the arc tube flows. The housing has three delivery ports disposed side by side as ports from each of which the cooling air is delivered into the space. A first delivery port included in the three delivery ports is located such that the center of the first delivery port is disposed substantially at a position aligned with the optical axis of the arc tube. Second and third delivery ports included in the three delivery ports are disposed in the vicinity of one and the other sides of the first delivery port, respectively, with respect to the optical axis.

CROSS-REFERENCE

The entire disclosure of Japanese Patent Application No. 2011-148007filed Jul. 4, 2011 is expressly incorporated herein.

BACKGROUND

1. Technical Field

The present invention relates to a light source device and a projector.

2. Related Art

A projector known in the art includes a light source device, a lightmodulation device which modulates light emitted from the light sourcedevice to form image light corresponding to image information, and aprojection lens which enlarges and projects the image light thus formedonto a screen or the like. A typical light source device included inthis projector contains a discharge-type arc tube such as an extra-highpressure mercury lamp. According to this type of light source device,the temperature of the arc tube increases during light emission.

In this case, the temperature of the upper part of the arc tube easilyrises, causing whitening of this part after continuation of the hightemperature condition. On the other hand, an excessive low temperatureof the lower part of the light emission portion causes blackening of thelower part. In either of these cases, the arc tube may lose itstransparency. Therefore, sufficient cooling is required for the upperpart of the arc tube to such an extent as not to excessively reduce thetemperature of the lower part of the arc tube.

JP-A-2010-212186 discloses a technology which includes a housingaccommodating an arc tube and a main reflection mirror. The housing hasa hollow column-shaped body disposed on the front side of the mainreflection mirror in the light emission direction in such a position asto surround the arc tube, and a duct member disposed on the outsidesurface of the column-shaped body as an air passage through which airflows in the circumferential direction of the column-shaped body. Thetop surface of the column-shaped body has an upper introduction portthrough which the air coming from the duct member goes into thecolumn-shaped body. The upper introduction port is disposed in such alocation that the center of the upper introduction port lies at aposition shifted from the center axis of the arc tube toward theupstream side with respect to the flow direction of the air within theduct member when the column-shaped body is viewed from above. Accordingto this structure, the flow passage of the duct member becomes shorter,and the resistance of the air flowing through the duct member decreases.Therefore, air having a sufficient flow speed and a sufficient flowamount can be securely introduced through the upper introduction portand supplied to the light emission portion.

According to the technology disclosed in JP-A-2010-212186, the arc tubeis cooled by using air supplied only through the one upper introductionport. However, the recent improvement over the light emission efficiencyof the arc tube (light emission portion) requires such a structure ofthe light source device which cools the arc tube with still higherefficiency. Therefore, development of a light source device and aprojector capable of cooling the arc tube with excellent efficiency hasbeen demanded.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the aforementioned problems and the invention can be implementedas the following application examples.

A light source device according to an application example of theinvention includes: an arc tube that has a light emission portion foremitting light; a reflector that reflects the light toward anillumination receiving area with the arc tube fixed to the reflector;and a housing that houses the reflector to form a space through whichcooling air for cooling the arc tube flows. The housing has threedelivery ports disposed side by side as ports from each of which thecooling air is delivered into the space. A first delivery port includedin the three delivery ports is located such that the center of the firstdelivery port is disposed substantially at a position aligned with theoptical axis of the arc tube as viewed in the vertical direction. Secondand third delivery ports included in the three delivery ports aredisposed in the vicinity of one and the other sides of the firstdelivery port, respectively, with respect to the optical axis as viewedin the vertical direction.

According to the light source device having this structure, the coolingair delivered from the first delivery port located such that the centerof the first delivery port is disposed substantially at a positionaligned with the optical axis of the arc tube is sandwiched between thecooling airs delivered from the second and third delivery ports disposedon the sides while flowing, in which condition the delivery direction(flow direction) of the cooling air can be kept constant. In this case,the cooling air can be appropriately supplied to the upper part of thearc tube only by the arrangement of the first delivery port such thatthe center of the first delivery port is disposed substantially at aposition aligned with the optical axis of the arc tube. Thus, theefficiency for cooling the arc tube improves.

In the light source device of the above application example, it ispreferable that channels at which the cooling air is branched into partsflowing through the second and third delivery ports in the light sourcedevice of the above aspect are inclined to the first delivery port whenthe three delivery ports are viewed in the vertical direction.

According to the light source device having this structure, the channelsat which the cooling air is branched into parts flowing through thesecond and third delivery ports are inclined to the direction of thefirst delivery port. In this case, the cooling airs delivered from thesecond and third delivery ports collide and mix with the cooling airdelivered from the first delivery port. As a result, cooling air whichincludes turbulent flow effective for cooling is produced. Accordingly,cooling efficiency for the arc tube can further improve.

In the light source device of the above application example, it ispreferable that the second and third delivery ports in the light sourcedevice of the above aspect are inclined to the first delivery port whenthe three delivery ports are viewed in the vertical direction.

According to the light source device having this structure, cooling airwhich includes turbulent flow effective for cooling is similarlyproduced when the second and third delivery ports are inclined to thedirection of the first delivery port. Accordingly, cooling efficiencyfor the arc tube can further improve.

In the light source device of the above application example, it ispreferable that the second and third delivery ports in the light sourcedevice of the above aspect are disposed substantially symmetric withrespect to the first delivery port when the three delivery ports areviewed in the vertical direction.

According to the light source device having this structure, the secondand third delivery ports are disposed substantially symmetric withrespect to the first delivery port. In this case, the cooling airsdelivered from the second and third delivery ports collide and mix withthe cooling air delivered from the first delivery port substantially atthe same position, in which condition the flow of the cooling air can beeasily controlled such that the flow direction becomes stable andlinear. Accordingly, the arc tube can be further efficiently cooled.

In the light source device of the above application example, it ispreferable that the three delivery ports in the light source device ofthe above aspect are provided such that the cooling air delivered fromthe first delivery port collides with the cooling airs delivered fromthe second and third delivery ports within the space between the firstdelivery port and the light emission portion.

According to the light source device having this structure, the coolingair delivered from the first delivery port collides and mixes with thecooling airs delivered from the second and third delivery ports withinthe space between the first delivery port and the light emissionportion. In this case, cooling air which has a stable flow direction andincludes turbulent flow effective for cooling is produced. This coolingair directly contacts the light emission portion, which further improvescooling efficiency for the light emission portion.

In the light source device of the above application example, it ispreferable that the three delivery ports in the light source device ofthe above aspect are provided such that the position where the coolingairs collide with each other is shifted toward the first delivery portfrom the middle between the first delivery port and the light emissionportion.

According to the light source device having this structure, the positionof collision lies at a position shifted toward the first delivery portfrom the middle between the first delivery port and the light emissionportion. In this case, the cooling air delivered from the first deliveryport collides with the cooling airs delivered from the second and thirddelivery ports in the upstream area within the space, wherefore the flowdirection of the cooling air within the space can be further stabilized.Thus, the light emission portion can be further efficiently cooled.

In the light source device of the above application example, it ispreferable that the housing in the light source device of the aboveaspect has another set of three delivery ports in addition to the set ofthe three delivery ports provided on the housing, the two sets of thethree delivery ports being disposed substantially symmetric with respectto the horizontal plane passing through the optical axis.

According to the light source device having this structure, the arc tubecan be cooled by using the three delivery ports either in the normalposition placed on an installation surface such as a desk, or in thesuspended position fixed to the ceiling or the like as the upside-downposition of the normal position. In this case, the arc tube can beefficiently cooled regardless of the difference in the position of thelight source device (normal position or suspended position).Accordingly, the life of the light source device increases.

A projector according to another application example of the inventionincludes any of the light source devices described above, and a lightmodulation device which modulates light emitted from the light sourcedevice according to image information.

The projector of this aspect of the invention includes the light sourcedevice capable of cooling the arc tube with higher efficiency, andtherefore can project image light having predetermined luminance for alonger period. This advantage is provided regardless of the differencein the position of the projector (normal position or suspendedposition).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 schematically illustrates the general structure of a projectoraccording to an embodiment.

FIG. 2 is a vertical cross-sectional view schematically illustrating alight source device main body.

FIGS. 3A and 3B are perspective views illustrating the externalappearance of a light source device.

FIG. 4 is a plan view of the light source device as viewed from above.

FIG. 5 is a perspective view of a first fixing frame.

FIG. 6 is a perspective view of the first fixing frame.

FIG. 7 schematically illustrates flow of cooling air when the lightsource device is viewed from above.

FIG. 8 schematically illustrates flow of cooling air when the lightsource device is viewed from the side.

DESCRIPTION OF EXEMPLARY EMBODIMENT

An embodiment according to the invention is hereinafter described withreference to the drawings.

Structure of Projector

FIG. 1 schematically illustrates the general structure of a projector 1according this embodiment. The projector 1 forms image lightcorresponding to image information and projects the image light onto ascreen (not shown). As illustrated in FIG. 1, the projector 1 chieflyincludes an external housing 2 constituting the external case, anoptical unit 3 housed within the external housing 2, a cooling fan 4,and others.

Structure of Optical Unit

The optical unit 3 forms image light corresponding to image information(image signals) under the control of a controller (not shown), andprojects the image light thus formed. As illustrated in FIG. 1, theoptical unit 3 includes a light source device 5, and an illuminationdevice 31 which has lens arrays 311 and 312, a polarization convertingelement 313, a stacking lens 314, and a collimating lens 315. Theoptical unit 3 also includes a color separation device 32 which hasdichroic mirrors 321 and 322 and a reflection mirror 323, and a relaydevice 33 which has an entrance side lens 331, a relay lens 333, andreflection mirror 332 and 334.

The optical unit 3 further includes an optical device 34 which has alight modulation unit constituted by three liquid crystal panels 341,three entrance side polarization plates 342, and three exit sidepolarization plates 343, and a color combining unit constituted by across dichroic prism 344, as well as a projection lens 35 as aprojection device which projects image light formed by the opticaldevice 34. The optical unit 3 still further includes an opticalcomponent housing 36 which houses the respective optical components 31through 34 at predetermined positions on an illumination optical axis Aestablished within the optical component housing 36.

According to the optical unit 3 thus constructed, light emitted from thelight source device 5 and transmitted through the illumination device 31is separated by the color separation device 32 into three color lightsof R light, G light, and B light. The respective separated color lightsare modulated by the corresponding liquid crystal panels 341 accordingto image information. The respective color lights thus modulated arecombined by the cross dichroic prism 344 into image light, and projectedthrough the projection lens 35 onto the screen.

The respective optical components 31 through 35 are similar to thecorresponding parts included in a projector of various types currentlyavailable, and therefore not specifically explained herein. In thefollowing description, therefore, the structure of the light sourcedevice 5 as the feature of the invention is only discussed.

Structure of Light Source Device

FIG. 2 is a vertical cross-sectional view schematically illustrating alight source device main body 5A.

FIG. 2 and later figures as depiction of this embodiment are shown byusing the XYZ rectangular coordinate system for the convenience ofexplanation. More specifically, in the normal position of the projector1, the Y direction corresponds to the direction of light emission fromthe light source device 5, i.e., the direction of the light sourcedevice 5 extending along the optical axis A. In this case, the +Ydirection is the direction in which light travels after emission. The Xdirection corresponds to the direction of light projection from theprojector 1. In this case, the +X direction is the direction in whichlight travels after projection from the projector 1. The Z directioncorresponds to the vertical direction crossing the Y direction and the Xdirection at right angles. In this case, the +Z direction is the upwardvertical direction (direction opposite to the direction of gravity).When viewed in the respective figures, the +Y direction corresponds tothe front direction (−Y direction: rear direction), the +X directioncorresponds to the left direction (−X direction: right direction), andthe +Z direction corresponds to the upward direction (−Z direction:downward direction).

As illustrated in FIG. 1, the light source device 5 includes the lightsource device main body 5A which has an arc tube 51 and a reflector 52,a collimating lens 54, and a housing 57 which houses these components.As illustrated in FIG. 2, the arc tube 51 has a light emission portion511 which expands in an approximately spherical shape, and a pair ofsealing portions 512 and 513 which extend in directions away from eachother from both ends of the light emission portion 511 with the lightemission portion 511 positioned between the sealing portions 512 and513. In the following description, the sealing portion 512 disposed onthe front side is referred to as the front sealing portion 512, whilethe sealing portion 513 disposed on the rear side is referred to as therear sealing portion 513, for the convenience of explanation.

The light emission portion 511 contains a pair of electrodes E1 and E2,between which electrodes E1 and E2 a discharge space is formed as aspace into which light emitting substances including mercury, rare gas,and a small amount of halogen are sealed. Metal foils 5121 and 5131 madeof molybdenum and electrically connected with the electrodes E1 and E2,respectively, are inserted into the corresponding sealing portions 512and 513. The ends of the respective sealing portions 512 and 513 on thesides opposite to the light emission portion 511 are sealed by glass orother materials.

The respective metal foils 5121 and 5131 connect with electrodeextension lines 514 and 515, respectively, which extend to the outsideof the arc tube 51. The electrode extension lines 514 and 515 are linesto which voltage is applied to cause light emission from the interior ofthe light emission portion 511. The electrode extension line 514 joinedwith the front sealing portion 512 further connects with one end of alead 516 which has a connection to a connector (not shown) providedoutside the light source device 5.

The reflector 52 has the function of reflecting received light toward apredetermined focus so that the reflected light can be convergedthereat. The arc tube 51 is fixed to the reflector 52 by junctionbetween a part of the rear sealing portion 513 and a cylindrical opening521 of the reflector 52 via an adhesive (not shown) in such a positionthat the light emission center of the light emission portion 511coincides with the focus of the reflector 52.

FIGS. 3A and 3B are perspective views illustrating the externalappearance of the light source device 5. More specifically, FIG. 3A is aperspective view of the light source device 5 as viewed from the upperfront, while FIG. 3B is a perspective view of the light source device 5from which a duct 8 is removed in the condition shown in FIG. 3A. Thesefigures illustrate the condition of the light source device 5 of theprojector 1 placed in the normal position.

As explained above, the light source device 5 includes the light sourcedevice main body 5A, the collimating lens 54, and the housing 57. Thehousing 57 which houses and fixes the light source device main body 5Aalso has the function of supporting the collimating lens 54. As can beseen from FIGS. 3A and 3B, the housing 57 chiefly includes a fixingframe body 7 and the duct 8.

The fixing frame body 7 has a first fixing frame 7A and a second fixingframe 7B. The first fixing frame 7A is a member which produces channelsfor cooling air when the duct 8 is fixed to the first fixing frame 7A.In addition, the first fixing frame 7A supports and fixes thecollimating lens 54. The second fixing frame 7B covers the back part(rear part) of the reflector 52 to protect a user of the projector 1from direct contact with the electrode extension line 515 extended fromthe rear sealing portion 513. The second fixing frame 7B is fixed to thefirst fixing frame 7A by screws to be combined with the first fixingframe 7A into one unit of the fixing frame body 7.

The second fixing frame 7B has openings 7B1 though which air isintroduced and supplied toward the outside surface of the reflector 52to cool the reflector 52. The second fixing frame 7B further has a grip7B2 held by the user when the light source device 5 is attached ordetached.

Structure of Duct

As illustrated in FIGS. 3A and 3B, the duct 8 is attached to the fixingframe body 7 (more specifically, a top surface 71, a bottom surface 72,and a right side surface 73 (described later) of the first fixing frame7A). The duct 8 has the function of guiding cooling air delivered fromthe cooling fan 4 (see FIG. 1) toward the interior of the first fixingframe 7A.

The duct 8 has a substantially U shape which is substantially symmetricwith respect to the X-Y plane passing through the illumination opticalaxis A. As illustrated in FIG. 3B, the inside of the duct 8 is an openspace provided as a hollow portion, so that channels can be producedwhen the duct 8 is attached to the first fixing frame 7A.

In the following description, the upper part of the duct 8 extended tothe left (+X direction) is called a second duct portion 82, the lowerpart of the duct 8 extended to the left (+X direction) is called a thirdduct portion 83, and the part of the duct 8 provided as a junctionbetween the second duct portion 82 and the third duct portion 83 andextended in the up-down direction (Z direction) is called a first ductportion 81.

The duct 8 accommodates a plate-shaped flow switching member 85supported at a position facing to an opening 811 in such a condition asto be freely rotatable. The flow switching member 85, which is designedto be freely rotatable around a pair of support shafts (not shown),rotates by its own weight to be inclined in the direction of gravity(inclined at approximately 45 degrees with respect to the Y direction inthis embodiment). The flow switching member 85 in the rotated conditioncloses the channel extending in the downward direction. Thus, coolingair introduced through the opening 811 collides with the flow switchingmember 85, thereby flowing in the direction opposite to the direction ofgravity (upward direction) either in the normal position or thesuspended position of the projector 1.

As illustrated in FIG. 3B, the duct 8 is slid in the direction from theright side surface 73 of the first fixing frame 7A (−X side) to the leftside surface 74 (+X side) to be fixed to the fixing frame body 7 (firstfixing frame 7A) by screws into one body. More specifically, the duct 8is slid from the right (−X side) to the left (+X side) with the secondduct portion 82 of the duct 8 shifted along an opening 71A (describedlater) of the top surface 71 of the first fixing frame 7A, and the thirdduct portion 83 of the duct 8 shifted along an opening (not shown) ofthe bottom surface 72 of the first fixing frame 7A. After the sliding toan appropriate position, the duct 8 is fixed by screws.

In the assembled condition, the duct 8 covers the top surface 71, thebottom surface 72, and the right side surface 73 of the first fixingframe 7A as illustrated in FIG. 3A. More specifically, the first ductportion 81 covers the right side surface 73 of the first fixing frame7A, the second duct portion 82 covers the top surface 71 of the firstfixing frame 7A, and the third duct portion 83 covers the bottom surface72 of the first fixing frame 7A. Under this condition, channels areproduced between the right side surface 73 and the first duct portion81, between the top surface 71 and the second duct portion 82, andbetween the bottom surface 72 and the third duct portion 83. Thesechannels are passages through which cooling air introduced via theopening 811 flows.

Structure of First Fixing Frame

FIG. 4 is a plan view illustrating the light source device 5 as viewedfrom above. This figure shows the light source device 5 from which thesecond fixing frame 7B and the duct 8 are removed. FIGS. 5 and 6 areperspective views of the first fixing frame 7A. More specifically, FIG.5 is a perspective view of the first fixing frame 7A as viewed from anupper (+Z side) front (+Y side) position, and FIG. 6 is a perspectiveview of the first fixing frame 7A as viewed from a lower (−Z side) rear(−Y side) position.

The first fixing frame 7A holds and fixes the light source device mainbody 5A and the collimating lens 54. As illustrated in FIG. 5, the firstfixing frame 7A has a substantially square pole box-like shape. Morespecifically, the first fixing frame 7A has the top surface 71 and thebottom surface 72 positioned in the up-down direction, and the rightside surface 73 and the left side surface 74 positioned in theleft-right direction. The first fixing frame 7A further has a frontsurface 75 and a rear surface 76 positioned in the front-rear direction.After the assembly for fixing the reflector 52 to the rear surface 76and supporting the collimating lens 54 by the front surface 75, thefirst fixing frame 7A forms a space S (see FIG. 7) through which coolingair flows toward the arc tube 51 as cooling air for the arc tube 51.

The top surface 71 of the first fixing frame 7A has the opening 71A opento the right and above. The opening 71A is closed by the duct 8 (secondduct portion 82). By this arrangement, the cooling air flowing withinthe duct 8 (first duct portion 81 and second duct portion 82) isintroduced into the first fixing frame 7A.

As illustrated in FIG. 5, the front surface 75 has a substantiallyoctangular opening 751 through which light emitted from the light sourcedevice main body 5A accommodated in the first fixing frame 7A passestoward the front. A guide portion 752 having a substantially octangularinner surface shape is provided on the front outside surface of theopening 751. The collimating lens 54 is inserted from the front (+Ydirection) into the guide portion 752.

After insertion of the collimating lens 54 into the guide portion 752, acollimating lens fixing frame 541 as an elastic component having asubstantially rectangular plate shape, at the center of which frame 541an opening 5411 is formed, is pressed from the front of the collimatinglens 54 against projections provided on the upper and lower parts (topsurface 71 side and bottom surface 72 side) of the front surface 75 ofthe first fixing frame 7A to be hooked to the projections as illustratedin FIGS. 3A and 3B. As a consequence, the collimating lens 54 issupported by the front surface 75 of the first fixing frame 7A and fixedthereto.

As illustrated in FIGS. 4 and 5, three delivery ports are providedinside the opening 71A of the first fixing frame 7A (top surface 71).These three delivery ports are constituted by a first delivery port 711disposed such that the center of the first delivery port 711 is locatedsubstantially at a position aligned with the illumination optical axis Aas viewed from the top (vertical direction), and a second delivery port712 and a third delivery port 713 disposed on one and the other sides ofthe first delivery port 711, respectively, with respect to theillumination optical axis A. More specifically, the first delivery port711 is positioned such that the center of the first delivery port 711lies substantially at a position in the vertical plane passing throughthe illumination optical axis A, and the second delivery port 712 andthe third delivery port 713 are positioned substantially symmetric withrespect to the first delivery port 711. The three delivery ports arearranged in the order of the second delivery port 712, the firstdelivery port 711, and the third delivery port 713 in the direction fromthe right (−X side) to the left (+X side).

As illustrated in FIGS. 4 and 5, three channels are further providedinside the opening 71A as passages through each of which partial airbranched from the cooling air flowing within the duct 8 (second ductportion 82) passes to enter the corresponding one of the three deliveryports. More specifically, the three channels are constituted by a firstchannel 711A through which air is introduced into the first deliveryport 711, a second channel 712A through which air is introduced into thesecond delivery port 712, and a third channel 713A through which air isintroduced into the third delivery port 713.

The second channel 712A has a wall 7121 and a groove 7122. The wall 7121blocks cooling air coming from the inside of the second duct portion 82to introduce a predetermined amount of cooling air through the groove7122 into the second delivery port 712.

The first channel 711A has a wall 7111, a groove 7112, and the wall 7121which forms the second channel 712A as well. The wall 7111 blockscooling air coming from the inside of the second duct portion 82 andflowing over the wall 7121 to introduce a predetermined amount ofcooling air through the groove 7112 into the first delivery port 711.

The third channel 713A has a wall 7131, a groove 7132, and the wall 7111which forms the first channel 711A as well. The wall 7131 blocks coolingair coming from the inside of the second duct portion 82 and flowingover the two walls 7121 and 7111 to introduce a predetermined amount ofcooling air through the groove 7132 into the third delivery port 713.The wall 7131 further functions as a wall for sealing the tip of theduct 8 (second duct portion 82).

As illustrated in FIG. 4, the wall 7121 and the groove 7122 of thesecond channel 712A, and the wall 7111 and the groove 7132 of the thirdchannel 713A are disposed symmetric with respect to the illuminationoptical axis A as viewed from above, and are inclined to the directionof the first delivery port 711. In this arrangement, the two deliveryports disposed on the sides (second delivery port 712 and third deliveryport 713) are similarly inclined to the first delivery port 711. Morespecifically, each of the second delivery port 712 and the thirddelivery port 713 is inclined to the center line of the illuminationoptical axis A at an angle α when the top surface 71 is viewed in thevertical direction (Z direction).

According to this structure, the first channel 711A becomes narrower inthe direction toward the first delivery port 711 by the inclinations ofthe walls 7111 and 7121 as illustrated in FIG. 4. In this case, thecooling air delivered from the first delivery port 711 has a pressurehigher than those of the cooling airs delivered from the second deliveryport 712 and the third delivery port 713 disposed on the sides, andbecomes jet flow when leaving the first delivery port 711.

An opening (not shown) opened to the right and below as an openingsubstantially similar to the opening 71A is formed on the bottom surface72 of the first fixing frame 7A. This opening is closed by the duct 8(third duct portion 83). Thus, in the suspended position of theprojector 1, cooling air introduced through the opening 811 and comingfrom the inside of the duct 8 (first dust portion 81 and third ductportion 83) flows into the first fixing frame 7A.

A structure similar to the structure of the channels and the deliveryports provided within the opening 71A of the top surface 71 is alsoequipped within the opening of the bottom surface 72 in such a mannerthat these structures within the top surface 71 and the bottom surface72 become symmetric with respect to the horizontal plane (X-Y plane)passing through the illumination optical axis A. Therefore, threedelivery ports (fourth delivery port, fifth delivery port, and sixthdelivery port, none of which is shown) are also provided incorrespondence with the three delivery ports discussed above (firstdelivery port 711, second delivery port 712, and third delivery port713) such that the two sets of the three delivery ports aresymmetrically disposed. Moreover, channels (not shown) associated withthe three delivery ports within the bottom surface 72 are similarlyequipped.

As illustrated in FIG. 6, the rear surface 76 of the first fixing frame7A has a substantially rectangular opening 76A opened to the rear (−Ydirection). A holding portion 767 is provided inside the rectangularopening 76A as a step concaved toward the inside. The light sourcedevice main body 5A is held by the contact between the holding portion767 and the tip of the reflector 52 including the corner edges thereof.

As illustrated in FIG. 6, the three delivery ports (first delivery port711, second delivery port 712, and third delivery port 713) disposedside by side below the holding portion 767 are exposed in the upper areaof the opening 76A (above the arc tube 51).

As illustrated in FIG. 6, the three delivery ports (first delivery port711, second delivery port 712, and third delivery port 713) arepositioned outside the opening 751 through which light passes. In otherwords, the three delivery ports are located outside the area throughwhich light reflected by the reflector 52 travels. The fourth deliveryport, the fifth delivery port, and the sixth delivery port are disposedin a similar manner.

As illustrated in FIGS. 5 and 6, a rectangular opening 731 is formed inthe wall extending from the opening 751 toward the right side surface73. This opening 731 provided substantially at the center of the wall inthe vertical direction is an opening through which a part of cooling airflowing through the duct 8 (first duct portion 81) is introduced intothe first fixing frame 7A (space S) and supplied chiefly toward thejunction between the electrode extension line 514 and the metal foil5121 of the arc tube 51 (front sealing portion 512) illustrated in FIG.2 to cool this junction area.

As illustrated in FIG. 6, a rectangular discharge port 741 is formed inthe wall of the left side surface 74 of the first fixing frame 7A. Thedischarge port 741 provided substantially at the center of the wall inthe vertical direction is an opening through which cooling air heatedafter flowing through the space S is discharged from the first fixingframe 7A (housing 57) to the outside.

Flow of Cooling Air

FIG. 7 schematically illustrates the flow of cooling air Ar when thelight source device 5 is viewed from above. FIG. 8 schematicallyillustrates the flow of the cooling air Ar when the light source device5 is viewed from the side (+X side). FIG. 7 shows the first fixing frame7A and the light source device main body 5A as viewed from above,including schematic cross sections of the first fixing frame 7A and thelight source device main body 5A located in the vicinity of the threedelivery ports. FIG. 8 is a cross-sectional view of the light sourcedevice 5 taken along the Y-Z plane passing through the illuminationoptical axis A. In FIGS. 7 and 8, the flow of the cooling air Ar isschematically illustrated by arrows.

Hereinafter discussed is the flow of the cooling air Ar which cools thelight source device 5 of the projector 1 placed in the normal position.

Cooling air (called “cooling air Ar”) delivered from the cooling fan 4(see FIG. 1) flows into the duct 8 via the opening 811 of the duct 8.The cooling air Ar introduced into the duct 8 flows through the firstduct portion 81 in the upward direction (+Z direction) by the guide ofthe flow switching member 85 (see FIG. 3A) rotatable by its own weight,and enters the second duct portion 82 connected with the first ductportion 81.

A part of the cooling air Ar introduced through the opening 811 isdelivered into the space S via the opening 731 (see FIG. 5). This partof the cooling air is supplied chiefly to the junction area between theelectrode extension line 514 and the metal foil 5121 of the arc tube 51(front sealing portion 512) shown in FIG. 2 to cool this junction areaas noted above. The cooling air heated after cooling the junction areais discharged through the discharge port 741 to the outside of thehousing 57.

As illustrated in FIG. 7, the cooling air Ar introduced into the secondduct portion 82 is branched into parts flowing along the first channel711A, the second channel 712A, and the third channel 713A, and deliveredfrom the first delivery port 711, the second delivery port 712, and thethird delivery port 713 into the space S. In the following description,the cooling air delivered from the first delivery port 711, the coolingair delivered from the second delivery port 712, and the cooling airdelivered from the third delivery port 713 are referred to as coolingair Ar1, cooling air Ar2, and cooling air Ar3, respectively.

As noted above, each of the second delivery port 712, the third deliveryport 713, the second channel 712A, and the third channel 713A isinclined to the direction of the first delivery port 711 (inclined tothe center line of the illumination optical axis A at the angle α).Thus, each of the cooling airs Ar2 and Ar3 is delivered with inclinationof the angle α (angle α in the horizontal plane (X-Y plane)) when thetop surface 71 is viewed in the vertical direction (Z direction) asillustrated in FIG. 7. The cooling air Ar1 is delivered in the directionalong the illumination optical axis A when the top surface 71 is viewedin the vertical direction.

As can be seen from FIG. 8, the three delivery ports are locatedsubstantially at the same position in the up-down direction as viewedfrom the side (X direction). Thus, the cooling airs Ar1, Ar2, and Ar3are delivered toward the light emission portion 511 substantially at thesame angle in the vertical plane (Y-Z plane) with respect to theillumination optical axis A as viewed from the side.

Each of the cooling airs Ar2 and Ar3 delivered from the second deliveryport 712 and the third delivery port 713 into the space S is inclined tothe cooling air Ar1 at the angle α. Thus, these cooling airs Ar2 and Ar3collide with the cooling air Ar1 delivered from the first delivery port711 at a position between the first delivery port 711 and the lightemission portion 511 as illustrated in FIG. 7. This collision positionis located in an area indicated as “B” in the figure in this embodiment.More specifically, as can be seen from FIG. 8, the area B is determinedat a position shifted toward the first delivery port 711 from a line Crepresenting the middle between the first delivery port 711 and thelight emission portion 511.

By collision between the cooling air Ar1 and the cooling airs Ar2 andAr3 supplied from the sides of the cooling air Ar1, these three coolingairs (cooling airs Ar1, Ar2, and Ar3) mix with each other. The mixedcooling air (hereinafter referred to as “cooling air Ar4”) flows towardthe light emission portion 511 to be supplied to the upper part of thelight emission portion 511 as illustrated in FIGS. 7 and 8. The coolingair Ar4 as a mixture of the three cooling airs (cooling airs Ar1, Ar2,and Ar3) has turbulent components effective for cooling, therebypromoting heat exchange during collision between the cooling air Ar4 andthe upper part of the light emission portion 511. Moreover, the flowdirection of the cooling air is linear and stable, which allows thecooling air to flow securely toward the upper part of the light emissionportion 511.

Moreover, the collision in the area B is located at a position shiftedtoward the first delivery port 711 from the line C representing themiddle between the first delivery port 711 and the light emissionportion 511. In this case, the flow direction of the cooling air Ar1(cooling air Ar4) can be stabilized in the upstream area of the space S.

The cooling air Ar4 supplied to the upper part of the light emissionportion 511 cools this part, while a part of the cooling air Ar4 flowingtoward the lower part of the light emission portion 511 cools the lowerpart of the light emission portion 511. The cooling air Ar4 also coolsthe whole internal area of the space S. The cooling air heated aftercooling the respective components is discharged through the dischargeport 741 (see FIG. 6) and the opening 521 of the reflector 52 (see FIG.2) to the outside of the housing 57.

While the flow of the cooling air Ar for cooling the light source device5 of the projector 1 placed in the normal position has been discussed,this course of flow also applies to the cooling air Ar for cooling thelight source device 5 of the projector 1 attached to the ceiling or thelike in the suspended position. The only difference is that the coolingair Ar for cooling the light source device 5 positioned upside downflows through the inside of the first duct portion 81 and the third ductportion 83 by the guide of the flow switching member 85, and then isbranched into parts each to be delivered through the corresponding oneof the fourth delivery port, the fifth delivery port, and sixth deliveryport.

As noted above, the set of the fourth delivery port, the fifth deliveryport, and the sixth delivery port and the set of the first delivery port711, the second delivery port 712, and the third delivery port 713 aredisposed substantially symmetric with respect to the horizontal plane(X-Y plane) passing through the illumination optical axis A. In thiscase, the flow of the cooling air Ar delivered from the fourth throughsixth delivery ports into the space S becomes similar to thecorresponding flow delivered from the first through third delivery ports711 through 713, and therefore the cooling action of the cooling air Arwithin the space S after delivery from the fourth through sixth deliveryports also becomes substantially equivalent. Thus, the same explanationof this action is not repeated herein.

According to this embodiment, the following advantages can be offered.

The housing 57 (first fixing frame 7A) of the light source device 5 inthis embodiment has three delivery ports through which cooling air isdelivered into the space S. These three delivery ports disposed abovethe arc tube 51 are constituted by the first delivery port 711 whosecenter is located substantially at a position aligned with theillumination optical axis A, and the second delivery port 712 and thethird delivery port 713 located on one and the other sides of the firstdelivery port 711. The pair of the second delivery port 712 and thethird delivery port 713, and the pair of the second channel 712A and thethird channel 713A are disposed symmetric with respect to the firstdelivery port 711, and each of the pair of the delivery ports 712 and713 and each of the pair of the channels 712A and 713A is inclined tothe first delivery port 711 at the angle α. According to this structure,the cooling airs Ar2 and Ar3 delivered from the second delivery port 712and the third delivery port 713 collide with the cooling air Ar1delivered from the first delivery port 711 substantially at the sameposition, and mix with the cooling air Ar1 thereat. As a result, thecooling air Ar4 which includes turbulent flow effective for cooling canbe produced, and the flow of the cooling air Ar4 (cooling air Ar1) thusproduced can be easily controlled such that the flow direction becomesstable and linear. Accordingly, the arc tube 51 (light emission portion511) can be cooled with high efficiency.

According to the light source device 5 in this embodiment, the coolingair Ar1 delivered from the first delivery port 711 of the housing 57(first fixing frame 7A) is directed toward the light emission portion511. Thus, the light emission portion 511 can be cooled by direct supplyof the cooling air Ar1. Moreover, the cooling airs Ar2 and Ar3 deliveredfrom the second delivery port 712 and the third delivery port 713disposed on the sides collide and mix with the cooling air Ar1, and thecooling air Ar4 as the mixture is supplied to the light emission portion511. Therefore, the light emission portion 511 can be cooled withexcellent efficiency.

According to the light source device 5 in this embodiment, the coolingair Ar1 delivered from the first delivery port 711 collides with thecooling airs Ar2 and Ar3 delivered from the second delivery port 712 andthe third delivery port 713 disposed on the sides, and mixes with thecooling airs Ar2 and Ar3 at the collision position in the space Sbetween the first delivery port 711 and the light emission portion 511.The mixing position (area B) is a position shifted toward the firstdelivery port 711 from the middle between the first delivery port 711and the light emission portion 511. According to this structure, thecooling air Ar1 collides and mixes with the cooling airs Ar2 and Ar3delivered from the second delivery port 712 and the third delivery port713 disposed on the sides immediately after the discharge from the firstdelivery port 711. In this case, the flow direction of the cooling airAr4 (cooling air Ar1) can be stabilized in the relatively upstream areawithin the space S, which contributes to further easy control over theposition of the cooling air Ar4. Therefore, the light emission portion511 can be further efficiently cooled.

According to the light source device 5 in this embodiment, the housing57 (first fixing frame 7A) has the three delivery ports (fourth deliveryport, fifth delivery port, and sixth delivery port) as well as the threedelivery ports (first delivery port 711, second delivery port 712, andthird delivery port 713) arranged such that the two sets of the threedelivery ports become substantially symmetric with respect to thehorizontal plane (X-Y plane) passing through the illumination opticalaxis A. According to this structure, the arc tube 51 can be cooled byusing the three delivery ports positioned above the arc tube 51 eitherin the normal position of the projector 1 placed on an installationsurface such as a desk, or in the suspended position of the projector 1fixed to the ceiling or the like as the upside-down position of thenormal position. In this case, the arc tube 51 can be efficiently cooledregardless of the difference in the position of the light source device5 (normal position or suspended position). Accordingly, the life of thelight source device 5 increases.

The projector 1 in this embodiment which includes the light sourcedevice 5 capable of cooling the arc tube 51 with higher efficiency canproject image light having predetermined luminance for a longer period.This advantage is provided regardless of the difference in the positionof the projector 1 (normal position or suspended position).

According to the projector 1 in this embodiment which includes the lightsource device 5 capable of cooling the arc tube 51 with higherefficiency, increase in the size of the cooling fan 4 and increase inthe driving voltage for the cooling fan 4 can be reduced to the minimum,for example, even when the luminance of the light source device mainbody 5A is raised. This structure contributes to prevention of sizeincrease and noise generation of the projector 1. When the lightemission efficiency of the arc tube 51 is equivalent to that of arelated-art arc tube, size decrease and noise reduction of the projector1 can be realized. This advantage can be offered regardless of thedifference in the position of the projector 1 (normal position orsuspended position).

In the foregoing specification, the invention has been described withreference to a specific embodiment thereof. It will, however, be evidentthat various modifications and changes, including the followings, may bemade thereto without departing from the scope and spirit of theinvention.

According to the light source device 5 in this embodiment, the coolingair Ar1 delivered from the first delivery port 711 collides and mixeswith the cooling airs Ar2 and Ar3 delivered from the second deliveryport 712 and the third delivery port 713 disposed on the sizes. However,each of the three delivery ports disposed adjacent to each other (forexample, first delivery port 711, second delivery port 712, and thirddelivery port 713) may supply cooling airs for each to the lightemission portion 511 without collision between each other in the courseof the delivery to the light emission portion 511. According to thisstructure, the cooling air delivered from the delivery port positionedat the center is sandwiched between the cooling airs delivered from thedelivery ports disposed on the sides during flow, in which condition thedelivery direction (flow direction) of the cooling air can be keptconstant. Thus, the flow direction of the cooling air can beappropriately controlled such that the cooling air can reach the upperpart of the arc tube 51 (light emission portion 511) and cool this partwith high efficiency.

According to the light source device 5 in this embodiment, the coolingair Ar1 delivered from the first delivery port 711 mixes with thecooling airs Ar2 and Ar3 delivered from the second delivery port 712 andthe third delivery port 713 at a position shifted toward the firstdelivery port 711 from the middle between the first delivery port 711and the light emission portion 511. However, the cooling air Ar1 may mixwith the cooling airs Ar2 and Ar3 at any position within the space Sbetween the first delivery port 711 and the light emission portion 511.

Each of the second delivery port 712 and the third delivery port 713provided on the first fixing frame 7A in this embodiment is disposedinclined to the first delivery port 711 at the angle α. According tothis structure, the cooling airs Ar2 and Ar3 delivered from the seconddelivery port 712 and the third delivery port 713 collide and mix withthe cooling air Ar1 delivered from the first delivery port 711substantially at the same position (area B). However, the respectiveangles of the second delivery port 712 and the third delivery port 713,and of the second channel 712A and the third channel 713A with respectto the first delivery port 711 are not required to be the same. In otherwords, the second delivery port 712 and the third delivery port 713, andthe second channel 712A and the third channel 713A may be arranged atany positions as long as they are inclined to the direction of the firstdelivery port 711. For example, the cooling airs Ar2 and Ar3 deliveredfrom the second delivery port 712 and the third delivery port 713 maycollide and mix with the cooling air Ar1 at different positions withrespect to the cooling air Ar1 delivered from the first delivery port711 as long as the cooling air Ar1 delivered from the first deliveryport 711 (cooling air Ar4 as mixture) can flow toward the cooling targetas a consequence.

According to this embodiment, each of the pair of the second deliveryport 712 and the third delivery port 713, and each of the pair of thesecond channel 712A and the third channel 713A provided on the firstfixing frame 7A is inclined to the first delivery port 711 at the angleα. However, such an arrangement is allowed in which each of only thepair of the second delivery port 712 and the third delivery port 713, orthe pair of the second channel 712A and the third channel 713A isinclined at the angle α. In any arrangements, the same advantage can beprovided as long as the cooling airs Ar2 and Ar3 are designed to collidewith the cooling air Ar1.

According to the light source device 5 in this embodiment, the seconddelivery port 712 and the third delivery port 713 are designed such thatthe air amounts and air pressures of the cooling airs Ar2 and Ar3delivered from the second delivery port 712 and the third delivery port713 into the space S become substantially equivalent. However, theamounts and pressures of the cooling airs Ar2 and Ar3 may be different.

The light source device main body 5A in this embodiment has the arc tube51 and the reflector 52. However, the light source device main body 5Amay be equipped with a so-called sub reflection mirror fixed to the arctube 51 in such a manner as to cover substantially half of the lightemission portion 511 on the front sealing portion 512 side so as toreflect light emitted from the light emission portion 511 toward thefront sealing portion 512 such that the light travels toward thereflector 52. This structure can offer advantages similar to those ofthis embodiment.

While the light source device 5 in this embodiment has the collimatinglens 54, the collimating lens 54 may be eliminated.

The arc tube 51 in this embodiment may be selected from various types ofdischarge-type lamps capable of emitting high-luminance light, such as ametal halide lamp, a high-pressure mercury lamp, and an extra-highpressure mercury lamp.

The optical unit 3 in this embodiment is of a so-called three plate typewhich includes three light modulation devices (liquid crystal panels341) corresponding to R light, G light, and B light. However, theoptical unit 3 may have a single plate type light modulation device inplace of the three plate type. The optical unit 3 may further include alight modulation device capable of improving contrast.

The optical unit 3 in this embodiment includes the transmission typelight modulation devices (transmission type liquid crystal panels).However, the optical unit 3 may include reflection type light modulationdevices.

The light modulation devices of the optical unit 3 in this embodimentare constituted by the liquid crystal panels 341. However, each of thelight modulation devices may be other types of light modulation deviceas long as they can modulate received light according to imageinformation, such as a micromirror type light modulation device. Forexample, a DMD (digital micromirror device) is an adaptable micromirrortype light modulation device.

According to this embodiment, the illumination device 31 contained inthe optical unit 3 as a unit for equalizing the illuminance of the lightemitted from the light source device 5 is constituted by a lensintegrator system including the lens arrays 311 and 312. However, a rodintegrator system including a light guide rod may be employed as theillumination device 31.

What is claimed is:
 1. A light source device comprising: an arc tubethat has a light emission portion for emitting light; a reflector thatreflects the light toward an illumination receiving area with the arctube fixed to the reflector; and a housing that houses the reflector toform a space through which cooling air for cooling the arc tube flows,wherein the housing has three delivery ports disposed side by side asports from each of which the cooling air is delivered toward thedirection of the light emission portion, a first delivery port includedin the three delivery ports is located such that the center of the firstdelivery port is disposed substantially at a position aligned with theoptical axis of the arc tube as viewed in the vertical direction, thehousing has three channels through which the cooling air flows to eachof the three delivery ports, second and third channels included in thethree channels are disposed in the vicinity of one and the other sidesof a first channel, respectively, with respect to the optical axis asviewed in the vertical direction, and each of the second and thirdchannels is inclined obliquely toward the direction of the first channelwhen the three channels are viewed in the vertical direction such that,prior to the cooling air reaching the light emission portion, thecooling air delivered from the first delivery port collides with thecooling airs delivered from the second and third delivery ports withinthe space between the first delivery port and the light emissionportion.
 2. The light source device according to claim 1, wherein thesecond and third channels at which the cooling air is respectivelybranched into parts flowing through second and third delivery ports areinclined to the first delivery port when the three delivery ports areviewed in the vertical direction.
 3. The light source device accordingto claim 1, wherein the second and third channels are inclined towardthe optical axis of the arc tube as viewed in the vertical direction. 4.The light source device according to claim 2, wherein second and thirddelivery ports are inclined toward the optical axis of the arc tube asviewed in the vertical direction.
 5. The light source device accordingto claim 2, wherein the second and third delivery ports are disposedsubstantially symmetric with respect to the first delivery port when thethree delivery ports are viewed in the vertical direction.
 6. The lightsource device according to claim 1, wherein the three channels areprovided such that the position where the cooling airs collide with eachother is shifted toward the first delivery port from the middle betweenthe first delivery port and the light emission portion.
 7. The lightsource device according to claim 1, wherein the housing has another setof three channels in addition to the set of the three channels providedon the housing, the two sets of the three channels being disposedsubstantially symmetric with respect to the horizontal plane passingthrough the optical axis.
 8. A projector comprising: the light sourcedevice according to claim 1; and a light modulation device whichmodulates light emitted from the light source device according to imageinformation.
 9. The projector according to claim 8, wherein the secondand third channels at which the cooling air is respectively branchedinto parts flowing through second and third delivery ports are inclinedto the first delivery port when the three delivery ports are viewed inthe vertical direction.
 10. The projector according to claim 8, whereinthe second and third channels are inclined toward the optical axis ofthe arc tube as viewed in the vertical direction.
 11. The projectoraccording to claim 9, wherein second and third delivery ports areinclined toward the optical axis of the arc tube as viewed in thevertical direction.
 12. The projector according to claim 9, wherein thesecond and third delivery ports are disposed substantially symmetricwith respect to the first delivery port when the three delivery portsare viewed in the vertical direction.
 13. The projector according toclaim 8, wherein the three channels are provided such that the positionwhere the cooling airs collide with each other is shifted toward thefirst delivery port from the middle between the first delivery port andthe light emission portion.
 14. The projector according to claim 8,wherein the housing has another set of three channels in addition to theset of the three channels provided on the housing, the two sets of thethree channels being disposed substantially symmetric with respect tothe horizontal plane passing through the optical axis.
 15. The lightsource device according to claim 1, wherein the second and thirdchannels are each inclined with respect to the first channel atsubstantially the same angle.